This invention generally relates to the manufacture of hollow containers made of synthetic materials, such as bottles, flasks, etc., by blow-molding or stretching-blowing of preforms, and more specifically to the feed of preforms to equipment used to manufacture the containers.
To manufacture certain types of containers, use may be made of preforms whose heads have a greater transverse dimension than their bodies. Because these preforms are initially bulk-loaded into a hopper, some of them, e.g., two, may become inserted into each other and, because of a wedging phenomenon, the means for feeding and positioning the preforms one by one on slide-tracks transporting the preforms to the container-manufacture machine are not capable of separating them. The interlocked preforms are thus transported on the conveyor slide-rails either in a vertical position, in which the lower preform rests on its head on the slide-rails in the same way as the separate preforms and is surmounted by the other interlocked preform or preforms, or in a horizontal position, in which the interlocked preforms lie flat on the slide-rails.
In any event, the interlocked preforms cannot be fed into the manufacturing machine. Vertically positioned interlocked preforms cannot reach the transfer apparatuses, since they exceed the size required for transport, while horizontally interlocked preforms cannot be grasped by the transfer apparatuses. As a result, the machine stops, thereby generating rejects and causing reduced production output. It is thus necessary to ensure that all of the preforms reaching the manufacturing machine are usable by the latter, by eliminating or rejecting the interlocked preforms before they reach the entrance to the machine.